The lockdown enforced in order to stop the spread of the coronavirus pandemic has seemingly made the world much quieter.
Seismologists around the world are observing a lot less ambient seismic noise-meaning the noise caused by cars, trains, buses, people etc.
Less ambient seismic noise has helped in reducing the vibration and movement in the Earth’s crust.
About Seismic Noise
In geological terms seismic noise refers to the vibration of the ground due to multitude of causes.
Seismic noise consists of surface waves categories in two parts:
- Low Frequency Waves(below 1 Hz) called Microseisms.
- High Frequency Waves(above 1 Hz) called Microtremors.
Seismic noise is caused by human activities( such as heavy machinery or traffic), winds, ocean waves and other atmospheric phenomena.
The Signals from the vibration of the ground is recorded by Seismometers.
Reasons For Reduction In Seismic Noise
Due to the containment measures taken globally to stop the spread of COVID-19 pandemic have seemingly made the world quieter, once crowded city streets are now empty, heavy traffic movement has slowed to a minimum which has significantly reduced the levels of vibrations caused in Earth’s crust.
Benefits From Reduction In Seismic Noise
The reduction in seismic noise has helped seismologists in detecting the smaller earthquakes and other seismic events that had slipped past the instruments so far and could not have been registered.
Seismic activity recording stations are generally set up outside urban areas as the ambient seismic noise in urban areas makes it harder to pick up subtle vibrations in the ground.